The invention relates to a centrifugal separator for separating liquid and/or solid particles from a gas flow, having a separator housing and having a rotor which can be set into rotation arranged therein, wherein the separator housing has a raw gas inlet, a clean gas outlet and a particle outlet as well as a circumferential wall which radially encloses the outside of the rotor at a distance therefrom, wherein a raw gas flow can be axially guided into the rotor and set into rotation therein, wherein a clean gas flow can be guided away radially out of the rotor and then between the outer circumference of the rotor and the inner circumference of the circumferential wall to the clean gas outlet, wherein the rotor has particle separation elements, by means of which particles which have been separated from the gas flow can be thrown off onto the inner circumference of the circumferential wall by centrifugal force, wherein the particles on the circumferential wall can be fed to the particle outlet and wherein at least one particle guide trough which runs at an angle to the axis direction of the rotor is arranged on the inner circumference of the circumferential wall.
A centrifugal separator of the kind mentioned above is disclosed in WO 2010/051994 A1. This separator has been proven in practice, but the relatively high manufacturing cost associated therewith is seen as disadvantageous. The high manufacturing cost results particularly from the fact that the circumferential wall with the particle guide trough can only be manufactured in one piece as an injection molded part or diecast part with the help of an elaborately designed injection mold with a spindle core. A disadvantage is also seen in that the circumferential wall with the particle guide trough is inserted in the separator housing as a separate sleeve, which gives rise to increased assembly cost. Furthermore, it has been shown in trials with this centrifugal separator that fine particles in particular are not separated from the gas flow in the desired quantity and with the desired efficiency.
A further centrifugal separator is disclosed in WO 2005/032723 A1. With this separator, a plurality, preferably between 5 and 40, of particle guide troughs which extend over at least the upper half of the rotor are provided on the circumferential wall, which leads to a higher manufacturing cost. Preferably, it is also provided here that the circumferential wall widens conically in the flow direction of the clean gas flow so that the distance between the outer circumference of the part of the rotor which throws off the particles and the inner circumference of the circumferential wall becomes greater towards the clean gas outlet in flow directions of the clean gas flow. As is known from trials with centrifugal separators of this kind, larger particles are predominantly thrown off in the lower part of the rotor while the thrown-off particles in the upper part of the rotor are smaller. As is also known, smaller particles have a lower inertia than larger particles which, in the case of this known centrifugal separator, leads to small particles thrown-off in the upper region of the rotor not reaching the circumferential wall due to the relatively large distance here but being carried to the clean gas outlet with the clean gas flow in an undesirable manner. This centrifugal separator therefore does not achieve optimal efficiency with regard to fine particles.